Technical description and composition of the LG 55LA790V TV, panel type and applicable modules. The composition of the modules.LG LED
Model: 55LA790V
Chassis / Version: LD34D
Panel: LC550EUH (LF) (F1)
LED backlight: 55 V13 ART TV REV 0.8 6 R / L-TYPE 6920L-0001C
LED driver (backlight): integrated into PSU
PWM LED driver: iW7011, R5F100BCAFP
MOSFET LED driver: TK15A20D, FDT86106LZ
Power Supply (PSU): EAX64905801 (2.0) LGP55-13LPB EAY62811001
PWM Power: ICE3BR4765JZ (Stb), R2A20133D (PFC), SSC9527S
MOSFET Power: STD13NM60N (PFC), STD10NM60N
MainBoard: EAX65040104-1.1 EBR77153002
IC MainBoard: LG1154AN, H5TQ4G63AFR
Tuner: TDSQ-G651D (B)
Technical Specifications 55LA790V
LG 55LA790V
General repair guidelines for TV LCD LED
Possible manifestations of defects
- LG 55LA790V does not turn on, the indicators on the front panel do not light or flash. The TV does not respond to the control buttons and the remote control.
Most often, with such manifestations, the main power supply module EAX64905801 is found to be faulty. It is necessary to measure its output voltages, and if they are absent (full or partial), you should check the health of the power switches (STD13NM60N (PFC), STD10NM60N) of the converters and rectifier diodes for a possible short circuit.
In case of breakdowns of diodes in the secondary circuits, the converter can operate in emergency short circuit mode without output voltages, and during short circuit in the power elements of the primary circuit, the mains fuse and / or current sensor at the source of the key usually breaks.
Breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback (OOS) stabilization circuits. PWM controllers (PWM) ICE3BR4765JZ (Stb), R2A20133D (PFC), SSC9527S, if they do not have visible damage to the case and open short circuit between the terminals, are usually checked by replacement.
- There is no image, there is sound, it responds to the remote control, the channels are switched. In some cases, the image appears when you turn on and immediately disappears.
Often in such cases, there is no LED backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
When diagnosing, it is necessary to take into account that it is impossible to check the open in the chain of LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally, a current source. By opening the panel, each LED can be checked separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect probes in the forward direction to it. In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as a health indicator. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- The indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the EAX65040104-1.1 motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). In cases of attempts to repair the MB board (SSB), it is necessary to check the serviceability of its elements - LG1154AN, H5TQ4G63AFR which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its conclusions with the board (it is diagnosed by heating).
If the TV works normally from external devices but does not tune into television channels, the tuner TDSQ-G651D (B) may be malfunctioning. In such cases, first of all, you should make sure that there are supply voltages at its corresponding conclusions. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the cause of the inoperability of the tuner may be a software failure.
Attention! For users and owners of 55LA790V TVs who do not have the appropriate qualifications, knowledge and experience, we strongly do not recommend attempting self-repair in order to avoid negative consequences that could lead to complete non-repairability of the device.
Service manual / schematic diagram ------------> LG 55LA790V Chassis LD34D.
PSU / schematic diagram ------------> LGP55-13LPB_EAY62811001_EAX64905801 Power supply
The appearance of the MainBoard EAX65040104-1.1 is shown in the figure below:EAX65040104-1.1
The appearance of the power supply
Main features of the device LG 55LA790V:
Installed matrix (LED-panel) LC550EUH (LF) (F1).
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by the iW7011, R5F100BCAFP PWM controller. As the power elements of the LED driver, keys of the type TK15A20D, FDT86106LZ are used.
The necessary supply voltages for all nodes of the LG 55LA790V TV are generated by the EAX64905801 power supply module or its analogs using ICE3BR4765JZ (Stb), R2A20133D (PFC), SSC9527S microcircuits and power switches of the STD13NM60N (PFC), STD10NM60N type.
MainBoard - the main board (motherboard) is an EAX65040104-1.1 module, using LG1154AN, H5TQ4G63AFR and other chips.
The TDSQ-G651D (B) tuner allows you to receive television programs and tune to channels.
Additional technical information about the panel:
Brand: LG Display
Model: LC550EUH-LFF1
Type: a-Si TFT-LCD, Panel
Diagonal size: 55 inch
Resolution: 1920x1080, FHD
Display Mode: S-IPS, Normally Black, Transmissive
Active Area: 1209.6x680.4 mm
Surface: Antiglare (Haze 1%), Hard coating (2H)
Brightness: 400 cd / m²
Contrast Ratio: 1500: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 8/10 (Tr / Td)
Frequency: 120Hz
Lamp Type: WLED Without Driver
Signal Interface: EPI, 100 pins
Voltage: 12.0V
